Intramedullary implant with proximal plate and method for its use

ABSTRACT

An orthopedic implant is specifically configured for use in osteotomies, in which part of the implant extends into an intramedullary portion of a first bone segment and a plate portion is external to the cortical surface of an adjacent bone segment to fix the segments to allow them to fuse. The body of the implant has a first end and a second end where the end which is inserted into the bone has a chamfer and a through hole having a hole axis optionally at an oblique angle to the longitudinal axis of the implant, and which can receive a screw, peg or pin. The second end of the implant includes a plate portion with at least two offset screws.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of patent application Ser. No.15/704,195, filed Sep. 14, 2017, which claims benefit of provisionalPatent Application No. 62/394,928, filed Sep. 15, 2016, the entiretiesof which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to an orthopedic intramedullary implant,which is configured for a minimally invasive procedure for the fixationof a bone or bones of the foot, hand or wrist in particular following aprocedure for fusion of adjacent segments or reconstruction such asvarious osteotomy procedures. The invention also relates to a method forthe use of the orthopedic implant and instruments for use with theimplant in surgical procedures.

BACKGROUND OF THE INVENTION

There are several conditions, such as hallux valgus, or more commonly“bunions”, which result from congenital deformation or which arise as aresult of repeated use type injuries. Surgical intervention thatincludes surgical sectioning of bone or an “osteotomy” is often used torestructure the bones as a treatment for such conditions. For example,the chevron translational osteotomy, of the first metatarsal with whichthe present invention might be used, is typically used to treat acondition that is the result of adult acquired metatarsal deformity. Thepresent invention is likewise useful for other conditions of the foot orhand that result from prior trauma, surgical intervention or defectsfrom birth or that develop with age (such as rheumatoid arthritis).

Examples of some of the procedures with which the present inventioncould be used include hallus valgus and hallus rigidus corrections, andbunionectomies. Other applications which could use the present inventioninclude first and fifth metatarsal chevrons, translational osteotomies,closing wedge osteotomies, pediatric femoral osteotomies, metacarpal andcalcaneal rotational osteotomies, intraarticular osteotomies and handand wrist realignment osteotomies.

SUMMARY OF THE INVENTION

In accordance with the present invention an orthopedic intramedullaryimplant (as well as a surgical method which uses the implant) isprovided which can be used to good advantage in an osteotomy. In a firstembodiment, the implant has a body having an exterior continuous curvedsurface formed around a long axis and configured to lodge within theintramedullary channel of the associated bone so as to avoid rotationwithin the channel. The body preferably has a basic shape (meaning anoutline exclusive of the optional flange, striation or groove meant tofurther stabilize the body in the intramedullary channel) whichpreferably forms a closed rounded cross-section including a circle oroval which can be the same dimension along the axis or not, to form athree dimensional figure such as a cylindrical, ellipsoid, torpedo, oregg shape. The body portion also has a first end that is tapered orsharpened for insertion, and a longitudinally opposing second end thateither cooperates with or extends into a plate portion so as to form anintegral substantially exclusive (meaning that the implant has only thebody and the plate, and no other arms, or plate members) two memberimplant that further includes means for fastening to the corticalsection of a bone. This first end (of the body member) includes arounded or tapered chamfered edge such as a counterbore that promotesinsertion into the bone. Between the first end and the second end, theimplant includes at least one through hole so that the implant can befixed through an extramedullary portion of a co-axial bone segment.Likewise, the plate portion includes one or more, and preferably two,offset through holes that receive cortical bone screws which areoptionally locking bone screws (i.e., including threads on the headwhich cooperate with internal threads on the through holes of the plateportion).

The invention can be used in a variety of indications including forexample, calcaneal osteotomies Dwyer osteotomy, cotton osteotomy,isolated TMT fusion, Navicular fracture, Evans osteotomy and metacarpalrotational osteotomies, or intraarticular osteotomies or hand and wristrealignment osteotomies. Other applications which could use the presentinvention include first and fifth metatarsal chevrons, translationalosteotomies, and closing wedge osteotomies.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 a is posterior view of a foot with a hallux valgus deformity

FIG. 1 b is a posterior view of a foot with the implant of the presentinvention following a translational chevron osteotomy procedure;

FIG. 2 is a side view of the orthopedic implant of FIG. 1(b);

FIG. 3 is a side view of the plate shown in FIG. 2 ;

FIG. 4 is an end view of the plate shown in FIG. 3 ;

FIG. 5 is a side detail of the plate portion of a second embodiment ofthe plate shown in FIG. 2 ;

FIG. 6 is a side detail of the plate portion of a third embodiment ofthe plate shown in FIG. 2

FIG. 7 is a side detail of the plate portion of a fourth embodiment ofthe plate shown in FIG. 2 ;

FIG. 8 is a side detail of the plate portion of a fifth embodiment ofthe plate shown in FIG. 2 ;

FIG. 9 is a side view of a first metatarsal illustrating the cuts for amethod of the present invention;

FIG. 10 is a side view of the metatarsal of FIG. 9 following theosteotomy and a counter-bore procedure to prepare for the implant of thepresent invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1(a) shows a skeletal version of a foot from the top sideillustrating a deformity with which the present implant could be used,and FIG. 1(b) shows the same version of the foot following the method ofthe present invention with an embodiment of the implant 10 of thepresent invention in place inserted into the intramedullary channel ofthe first metatarsal following an osteotomy and the translation of thedistal portion of the metatarsal. Thus, FIG. 1(b) illustrates theimplant used in a translational osteotomy of the first metatarsal fortreatment of hallux valgus syndrome. Similarly, it can be used forfixation of other bone segments following osteotomies as previouslymentioned.

As viewed from the top in FIG. 1(b), it can be seen that the firstembodiment of the plate 10 has a body member 11 shaped for insertioninto the intramedullary portion of the bone following the osteotomy witha first end 12 that extends into a plate portion 13 and an opposingcutting end 14 aligned along the longitudinal axis of the plate whichfurther includes a cannulation 16 which extends through the body memberto allow for the insertion or use of a k-wire. The body of the implantfurther includes a through hole 17 closer to the second end than thefirst which again is optionally threaded, for a screw 18 which isoptionally a locking screw. The screw is intended to inhibit rotation ofthe implant in the channel. The body portion is sized and shaped forinsertion into the intramedullary channel of a bone, for example, it maybe cylindrical or ellipsoid, or have an elongate shape that isrelatively round in cross-section but which is less regular than acylinder or ellipse. The outer surface may be smooth, or may include oneor more raised portions 15 (illustrated in FIG. 4 ), such as grooves,flutes or flanges which extend parallel to the cannulation part of allof the way down the length of the body member or which spiral around thebody member) in order to inhibit the implant from rotating within theinner portion of the bone.

The plate portion 13 has a profile when viewed straight on in the widestdimension which is sized to accommodate the specific application, inthis case so that it will best conform to the remaining head of themetatarsal, and further includes at least a first through hole 20(optionally threaded) for a screw 24 (optionally locking) and preferablya second through hole 22 (also optionally threaded) for a second screw26 (again optionally locking). Specifically, in the illustratedapplication for a bunionectomy, the plate portion has an outline viewedfrom the outer surface of a tab or partial egg shape, and the bonefacing surface is curved so as to form a section of a cylinder(corresponding to an idealized shape of the head of the associatedmetatarsal).

FIGS. 5 through 8 illustrate various embodiments of the implant 10, inwhich the plate portion is offset to accommodate particular anatomicalvariations, of ⅓ of the distance across the diameter at the top surfaceof the implant in FIG. 5 , of ⅔ of the distance across the diameter atthe top surface of the implant in FIG. 6 , and of ⅞ of the distanceacross the diameter at the top surface of the implant in FIG. 7 , and inFIG. 8 , the plate portion is angled at from 2° to 15°, and preferablyfrom 7° to 12° relative to the axis of the body member to inhibit aVarus tilt. Further this drawing illustrates the body and plate as anassembly, as compared to the other integrally formed plate and bodymembers. In FIG. 8 , the plate portion 413 extends from a threaded tapmember 30 that is received in a threaded screw hole 32 in the bodymember. In this embodiment, various plate portions with varying degreesand/or angles of offset can be used in the body member to simplify theinventory of the system.

FIGS. 9 and 10 illustrate steps of the surgical procedure of the presentinvention where in FIG. 9 multiple incisions are made to the head and atabout 1 cm down the neck of the metatarsal. Next, a tool is placed totranslate the head of the metatarsal laterally and the remainingproximal portion of the bone is reamed in an Eichhorn shape as is shownin FIG. 10 . Next with pushing or drilling, a k-wire is placed in themetatarsal to the base, and the bone is reamed by power or hand. Theguide wire is left in place. Then the implant is pushed into positionover the guide wire and into the intramedullary channel using across-jig which is radiographically located. The screws are insertedinto the plate portion, and the implant is pushed into the proximalportion of the bone to compress. The cross screw is inserted, the jigsare disassembled and the guide wire is removed, the medial ledge isremoved, including a saw is used or a burr if a mini-incision is used.Graft is added as needed and the incision is closed.

The screws useful with the plate of the present invention areself-starting, self-tapping screws including the option of partial orfull cannulation. The screws include a cutting end having multipleflutes, and preferably 2 or 3 flutes about a conical recess. The screwsfurther include a partial taper of the inner diameter in the proximalend over the first several thread turns, for example over 2-8, andpreferably over 3-5 turns in order to increase the fatigue life of thescrew as well as providing potential physiological advantages in use.The screws further include a torque driving recess. The screws have athreaded distal end and a head including a torque driving recess. Thehead of the locking screw includes locking means, such as a variablelocking mechanism, which could be a bushing that mates with the screwhead so as to lock the screw relative to the plate at a desired angle,or could include external screw threads that mate with internal threadsin the locking screw hole at a pre-selected angle, in this instance, thescrew axis is perpendicular to the longitudinal axis of the plate. Thescrew used in the anti-rotation slot has a rounded rear shoulder (suchas a hemisphere, or a torroid) which mates with the edges of the slot.

The implant is formed of a biocompatible material, and preferably ametal such as surgical grade stainless steel, titanium or a titaniumalloy or a cobalt chromium alloy. Preferably, the plate portion has athickness of between about 1.0 and about 2.5 millimeters, morepreferably between about 1.5 and about 2 millimeters, and mostpreferably between about 1.5 and about 1.8 millimeters. The body portionof the implant has a curved cross-section having a diameter defining atotal thickness of about 4 and 8 millimeters, or roughly four times thewidth of the plate portion of the implant.

In addition, the implant can include additional small through holessized to receive a K-wire or other similar guide wire.

During the surgery the joints are first prepped which may includede-articulation between the bones to be fused and removal of any bone aspart of the osteotomy, and as necessary, the plate is bent to contour tothe bone surface. A pilot hole or preferably, an Eichhorn shaped recessmay be drilled into the bone into which the implant will be inserted.The implant is inserted into the implant recess in the driver andsecured by tightening the implant upward in the holder using the holder.The implant is tamped into the cancellous portion of the bone fragmentoptionally by tapping the implant driver with a one pound mallet as isnecessary to insert the body of the implant. The implant should bedriven until it is fully seated. Once the implant is sunk, a drill guideis mated to the driver, and a hole is drilled for the transverse screw.The implant can be held in position using k-wires or olive wires (thruthe non-locking hole and into the bone). The plate portion is locatedsuch that all of the screws are aimed into the targeted bones and awayfrom the joint, fracture, or bone interface. The olive wire is removedif used, and a pilot hole is drilled at the end of the plate thatincludes the first hole and this hole is pinned or screwed. A secondpilot hole may be drilled for the transverse. The plate is viewedradiographically, and the soft tissues are closed in the usual manner.

This invention has been described in detail with reference to specificembodiments thereof, including the respective best modes for carryingout each embodiment. It shall be understood that these illustrations areby way of example and not by way of limitation.

What is claimed is:
 1. An implant for an osteotomy of an associated longbone, comprising: a plate fastener and a body fastener; a plateconfigured to cooperate with a cortical surface of a bone, and includingone or more through holes suitable for receiving the plate fastener; anda body having a chamfered first end and a second end joined by acontinuous curved exterior surface with a through hole in the body thatdefines an angle for the body fastener that is perpendicular to the longaxis of the body, configured to lodge within the intramedullary channelof a long bone so as to avoid rotation (i) within the channel and (ii)about the osteotomy site, the first end being tapered and the second endextending into the plate so as to form an integral two member implant.2. An implant as set forth in claim 1, wherein the first end includes acounterbore.
 3. An implant as set forth in claim 1, wherein the plateincludes two through holes each arranged so as to receive at least onefastener.
 4. An implant as set forth in claim 3, wherein the throughholes are locking through holes and the fasteners are locking fasteners.5. An implant as set forth in claim 4, wherein the plate is a separateportion of the implant that is joined to the body in advance of asurgery.
 6. An implant as set forth in claim 5, wherein the plate isoffset from the long axis of the body.
 7. An implant as set forth inclaim 6, further comprising a system having at least two plate portions.8. An implant as set forth in claim 1, wherein the through hole in theplate is offset from the long axis.
 9. An implant as set forth in claim1, wherein the bottom surface of the plate defines a longitudinal axisand includes a radius of curvature defined along the longitudinal axis.10. An implant as set forth in claim 9, wherein the plate is defined bya portion of a cylinder.
 11. A surgical procedure for a metatarsal bonecomprising: making at least one incision to a head of a metatarsal so asto form a 0.5-1.5 cm incision down a neck of the metatarsal; translatingthe head of the metatarsal laterally; reaming a proximal portion of themetatarsal so as to form a recess having a base in a intramedullarychannel; placing a k-wire in the metatarsal at the base of the recessand leaving the guide wire in position while an implant, having a bodyand a plate with a screw hole, into position over the guiding k-wire andinto the intramedullary channel; and inserting at least one screwthrough the screw hole in the plate and into the cortical surface of themetatarsal head.
 12. The surgical procedure as set forth in claim 11,wherein the body includes a through hole with a screw placed through thethrough hole.
 13. An implant for an osteotomy of a long bone,comprising: a plate configured to cooperate with a cortical surface,including one or more through holes arranged and configured forreceiving a fastener; and a body having a first end and a second endjoined together by a curved exterior surface formed along a long axis,configured to lodge within an intramedullary channel of a long bone, thecurved exterior surface including at least one of grooves, flutes andflanges that are arranged in parallel relation to one another so as toprovide for inhibition of implant rotation within the bone, the firstend being sharpened to facilitate insertion into the long bone anddefining a threaded through hole adjacent to the sharpened portion ofthe first end and configured to receive a threaded fastener, wherein thesecond end extends into the plate so as to form an integral two memberimplant.
 14. An implant for an osteotomy of a long bone comprising: afirst portion configured to cooperate with a cortical surface of a bone,and including at least one through hole; and a cannulated body having afirst end and a second end joined by a curved exterior surface formedalong a long axis, configured to lodge within an intramedullary channelof a long bone, the curved exterior surface including at least one ofgrooves, flutes and flanges that spiral around the body and arranged intapering, spaced circumferential relation to the cannulation so as toinhibit the implant from rotating within the bone, the first end beingtapered to facilitate insertion into the long bone with a threadedthrough hole defined adjacent to the taper and configured to receive athreaded fastener, and the second end extending into the first portionso as to form an integral two member implant.